Re: [Histonet] Question about molecular sieves for EtOh

From:

Philip Oshel

René,
Anhydrous copper sulfate works, but it has a
worse dust problem than does molecular sieve.
Also, molecular sieve can hold 3 to 4 times more
water (on a weight basis) than can copper sulfate.
Copper sulfate is cheaper, but in the long run, I
think sieve is cheaper. Buy 5 pound cans from
e.g. Fisher.
Note: don't buy either of these with indicator!
The indicator dye dissolves in the alcohol.
Both can be regenerated (dried) in a 200 deg C
oven for 3 hours or so, then re-used.
Phil
>Lawrence:
> If you want to have really anhydrous EtOH, why
>don't you just add an excess of anhydrous copper
>sulfate (white powder) that will absorb any
>water in the EtOH?
> I used this method for years and changed the
>powder when it began to turn blue.
> Copper sulfate anh. will not only dehydrate
>the EtOH but will indicate you also when to
>change it and probably will be cheaper that your
>present method.
> Hope this will help you!
> René J.
>
>Lawrence D Lanberg/O/VCU wrote:
>
>Dear Histonet Community,
>
>Today I added 3A bead molecular sieves to my EtOh, so I can have
>(hopefully) a better tissue dehydration tomorrow. But the ethanol took on
>quite a murky appearance. It seemed that after a few hours it cleared, just
>a tiny bit. But it still looks kind of scary.
>
>Does this go away completely -- with longer sitting of the ethanol??? Or
>does anybody know a good way to separate, without the chance of humidity
>getting back into the EtOh?
>
>Thanks so much.
>
>Larry Lanberg
--
Philip Oshel
Microscopy Facility Supervisor
Department of Biology
Central Michigan University
024C Brooks Hall
Mt. Pleasant, MI 48859
voice: (989) 774-3576
dept. fax: (989) 774-3462
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